It's worth about £20 so I offer you £19 :lol:
No, seriously. The PSP gigapack retails for just over £200 (
www.play.com but you might find it cheaper elsewhere), so with the two games I reckon you are talking about £160-£180 depending on the condition. If it's virtually new, boxed and in mint condition you should be able to get about £180 but don't quote me on that.